Clinical Neuroimaging Peculiarities and Functional Consequences of Ischemic Stroke in Patients with MS

The objective of the research was to study the peculiarities of post-stroke period in patients with metabolic syndrome (MS), functional consequences, cognitive impairment, to identify structural brain changes on the basis of MRI results; to perform correlation analysis between the brain volumetric test results and cognitive deficit.Materials and methods. The study involved 116 patients, aged 51 to 81, with ischemic stroke, 79 patients – main group – during the early and late recovery periods after ischemic stroke related to MS. The control group included 37 patients in the early and late recovery periods after acute cerebrovascular accident (ACVA) without MS. To determine the functional consequences of ischemic stroke after 12 weeks and 1 year after it, the examination was conducted and the results were evaluated according to modified Rankine scale (MSHR) and Barthel Index (BI). We determined patients’ mortality rate within 1 year after the ischemic stroke. Their condition of cognitive functions was measured according to MMSE, MOSA and FAB scales. The volume of cortex and white matter of the cerebral hemispheres, temporal and frontal lobes were measureed (cm³) by applying MRI scanner Toshiba Vantage Titan 1,5. Workstation Vitrea was used for images post-processing.Results. Patients with MS had more common significant signs (p<0.05) of neurological status functional disorders, delayed recovery and disability. Within a year, in the main group mortality rate because of recurrent stroke was 5.06%, which was significantly higher than in the control group, where the mortality rate was 2.7%. Within a year, the process of lost functions restoring according to MSHR occurred in both groups, but in the main group, this rate was significantly lower in comparison to the control group. Patients with MS were determined to have a significant impairment of cognitive functions according to cognitive scales. However, a year later cognitive performance did not differ significantly in the main and control groups, although they declined in both groups. Volumetric parameters were determined: the volume of cortex and white matter of the cerebral hemispheres, temporal and frontal lobes (cm³). Results obtained: reduced total volume of the brain, of the temporal and frontal lobes in patients of the main group (p<0.05). Patients of both study groups were determined to have cognitive functions impairment - reduced volume of the cortex in the frontal and temporal lobes according to MMSE scale. The correlation index between cortex indicators of frontal and temporal lobes volume and the results of cognitive functions according to MMSE scale was: r = 0,62 - temporal and r = 0,59 frontal lobes indicators. Modules of correlation coefficients were within the average strength.Conclusions. Patients who have suffered from primary ischemic stroke related to MS restored their lost functions slower and the mortality rate among them was significantly higher (p<0.05) within the first year after stroke than in patients without MS. Patients had cognitive deficits related to cortex atrophy in the frontal and temporal lobes after the primary ischemic stroke. Atrophy in these areas of the cortex was more distinct (p<0.05) than in patients without MS. Positive correlation relationship was determined between cognitive performance and the degree of cortex atrophy in the frontal (r = 0.59) and temporal (r = 0.62) lobes of patients with ischemic stroke related to MS

Structural and Volumetric Characteristics of Cerebral Damage in Patients with Metabolic Syndrome

The objective of the research was to identify volumetric brain indicators (hippocampal volume) in patients with chronic cerebral ischemia secondary to metabolic syndrome (MS) in comparison with patients suffering from chronic cerebral ischemia without MS; to identify hippocampal index as well as medial, lateral and upper perihippocampal indices in patients with MS in comparison with those in patients without MS.Materials and methods. Hippocampal volume of 47 patients (29 patients with MS - the main group and 18 patients without MS – the control group) was evaluated by means of volumetric method. During 49 studies (28 - the main group and 21 - the control group) the size of the hippocampus and perihippocampal cerebrospinal fluid space was measured.Results and discussion. We determined a significant increase (*P<0.05 in comparison with the control group) in the lateral perihippocampal cerebrospinal fluid space (cm) in the main group in comparison with the control group (Me [Q1, Q3]): on the right it was 2.90 [2.75 ; 2.96]  vs. 2.21 [1.82; 2.05] in the control group (р<0.05); on the left it was 2.97 [2.75; 2.96] vs. 2.275 [2.15; 2.76] in the control group (р>0.05). A significant decrease in the index of the right and left hippocampus was determined in patients with MS in comparison to the patients of the control group (Me [Q1,Q3]): on the right it was 0.50 [0.41; 0.54] vs. 0.594 [0.58; 0.61]; on the left it was 0.56 [0.52; 0.60] vs. 0.61 [0.58; 0.63] in the control group (р<0.05). A significant difference in the increase of the medial and upper perihippocampal indices on either side was defined in the main group in comparison with the control one. Lateral perihippocampal index did not significantly differ from the control group (р>0.05). Determination of the hippocampal volume (right and left) showed that it was significantly lower in patients with MS than in patients without MS (Me [Q1,Q3]): on the right it was 3.293058* [2.92616; 3.04016] in the main group, and 3.93 [3.72750; 4.29722] in the control group; on the left it was 2.84 [2.65; 3.02] * in the main group, and 3.55 [3.22, 3.7] in the control group. Components of MS cluster in patients with chronic cerebrovascular pathology are likely to contribute to the development of atrophic processes. The combination of hypertension, insulin resistance, dyslipidemia, etc. accelerate the processes of hippocampal atrophy more than each of these separate components determined in patients with chronic cerebral ischemia without MS.Conclusions. Thus, the degree of hippocampal atrophy in patients with chronic cerebrovascular diseases secondary to MS was defined to be significantly higher in comparison with patients without MS. To improve diagnosis of cerebrovascular diseases in patients with MS, it is possible to apply the identification of hippocampal index and perihippocampal indices if it is not possible to determine the volume of brain structures.

Anomalies of Density, Stresses, and the Gravitational Field in the Interior of Mars

We determined the possible compensation depths for relief harmonics of different degrees and orders. The relief is shown to be completely compensated within the depth range of 0 to 1400 km. The lateral distributions of compensation masses are determined at these depths and the maps are constructed. The possible nonisostatic vertical stresses in the crust and mantle of Mars are estimated to be 64 MPa in compression and 20 MPa in tension. The relief anomalies of the Tharsis volcanic plateau and symmetric feature in the eastern hemisphere could have arisen and been maintained dynamically due to two plumes in the mantle substance that are enriched with fluids. The plumes that originate at the core of Mars can arise and be maintained by the anomalies of the inner gravitational field achieving +800 mGal in the region of plume formation, - 1200 mGal above the lower mantle-core transition layer, and -1400 mGal at the crust.Comment: 9 pages, 5 figure

Postslaughter state of muscle tissue of pigs depending on the duration of pre-slaughter fasting

Changes in the muscle tissue microstructure lead to changes in meat quality. One of the causes of the myopathy development is animal stress. Pigs experience the strongest stress during pre-slaughter holding. The study of the postmortem meat structure depending on fasting time is a topical task. The objects of the research were samples of m. L. dorsi obtained after slaughter from pigs that differed in fasting time: 4 (group 1), 8 (group 2), 10 (group 3), 16 (group 4) and 18 (group 5) hours (N = 20, n = 4). Investigation of the microstructure and morphometric measurements were carried out on preparations stained with hematoxylin and eosin. Myopathic changes in muscle tissue were assessed using a semi-quantitative method developed earlier. All studied samples were characterized by the uniform condition of muscle tissue. Statistically significant differences between individual groups were observed regarding the number and area of giant fibers, sarcomere length, diameter of muscle fibers and proportion of muscle fibers, which diameter was lower or higher by 1/3 than the mean fiber diameter. An increase in the pre-slaughter holding time reduced the number and area of giant fibers (r = –0.8437 and –0.5796, respectively), as well as the diameter of “normal” fibers (r = –0.5337), which positively influenced pork quality. Groups 1, 2 and 3 were characterized by the presence of signs of moderate and pronounced myopathy. Only one carcass with pronounced myopathic signs was revealed in each of groups 4 and 5. In group 4, one carcass did not have signs of myopathy. Pre-slaughter holding during 4, 8 and 10 hours led to deterioration of pork quality. The recommended fasting time is 16 hours

Modelling radiation-induced cell cycle delays

Ionizing radiation is known to delay the cell cycle progression. In particular after particle exposure significant delays have been observed and it has been shown that the extent of delay affects the expression of damage such as chromosome aberrations. Thus, to predict how cells respond to ionizing radiation and to derive reliable estimates of radiation risks, information about radiation-induced cell cycle perturbations is required. In the present study we describe and apply a method for retrieval of information about the time-course of all cell cycle phases from experimental data on the mitotic index only. We study the progression of mammalian cells through the cell cycle after exposure. The analysis reveals a prolonged block of damaged cells in the G2 phase. Furthermore, by performing an error analysis on simulated data valuable information for the design of experimental studies has been obtained. The analysis showed that the number of cells analyzed in an experimental sample should be at least 100 to obtain a relative error less than 20%.Comment: 19 pages, 11 figures, accepted for publication in Radiation and Environmental Biophysic

ХАРАКТЕРИСТИКИ ОСЛАБЛЕНИЯ И ОТРАЖЕНИЯ ЭЛЕКТРОМАГНИТНЫХ ВОЛН МАТЕРИАЛАМИ НА ОСНОВЕ СШИТОГО ПОЛИМЕРНОГО ГИДРОГЕЛЯ

The shielding characteristics of hydrophilic polymer, which is a crosslinked polyelectrolyte hydrogels and used for developing of flexible modules for electromagnetic radiation shields, are studied.Исследованы экранирующие характеристики гидрофильного полимера, представляющего собой сшитый полиэлектролитный гидрогель, на основе которого были сформированы гибкие модули для экрана электромагнитного излучения

ПОГЛОТИТЕЛИ ЭЛЕКТРОМАГНИТНОГО ИЗЛУЧЕНИЯ НА ОСНОВЕ ПОРОШКООБРАЗНОГО ТОРФА В ПОЛИМЕРНОМ СВЯЗУЮЩЕМ ИЗ ГИДРОГЕЛЯ

The influence of the type and volume content of powdered peat on the shielding characteristics of composite materials was investigated in the frequency range of 8…12 GHz. It was shown, that the transmission and reflection coefficients slightly differ for various types of peat components and mainly depend on the volume content and the layer thickness. The transmission coefficient for the studied materials varies in the range of -4.5…-2.1 dB and the reflection coefficient - in the range of -12.2…-8.2 dB.Исследовано влияние типа и объемного содержания порошкообразного торфонаполнителя в составе композиционных материалов на характеристики экранирования электромагнитного излучения в диапазоне частот 8…12 ГГц. Показано, что коэффициенты передачи и отражения ЭМИ незначительно изменяются для различных видов торфяного сырья и в основном определяются объемным содержанием компонентов и толщиной слоя. Коэффициент передачи исследованных материалов изменяется в пределах -4,5…-2,1 дБ и коэффициент отражения в пределах -12,2…-8,2 дБ